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Taiwan Semiconductor Corporation SMAJ22CH
- Part No.:
- SMAJ22CH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ22CH.pdf
- Description:
- TVS DIODE 22VWM 39.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:3,158
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Product details
Overview
SMAJ22CH from Taiwan Semiconductor is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, with 22V working stand-off voltage (VWM), 24.4–29.8V breakdown voltage (VBR), and 39.4V clamping voltage (VC) at 10.2A peak pulse current under 10/1000μs waveform-designed for robust overvoltage protection in automotive DC/DC converters.
For engineers reviewing the SMAJ22CH datasheet, SMAJ22CH pinout, SMAJ22CH application, or SMAJ22CH equivalent, key selection criteria include clamping performance at rated surge current, AEC-Q101 qualification for automotive environments, moisture sensitivity level (MSL 1), and compatibility with automated SMT placement on high-reliability power rails.
Technical Context
The SMAJ22CH operates as a unidirectional avalanche diode, triggered when reverse voltage exceeds its VBR range (24.4–29.8V @ 1mA), limiting transients to ≤39.4V at 10.2A. Its glass-passivated junction ensures stable leakage (<1μA @ 22V) and fast response (<1.0ps).
It meets ISO 7637-2 Pulse 1/2a/2b/3a/3b immunity requirements and is rated for TJ = –55°C to +150°C operation, supporting under-hood automotive applications where thermal derating and pulse survivability are critical.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 22 V - Maximum continuous reverse operating voltage before conduction begins |
| VBR min/max | 24.4 V / 29.8 V @ 1 mA - Ensures reliable turn-on margin above VWM with production tolerance |
| VC @ IPPM | 39.4 V @ 10.2 A (10/1000μs) - Clamping voltage defines worst-case rail overshoot during surge |
| PPPM | 400 W - Peak pulse power handling capacity per standard 10/1000μs waveform |
| IR @ VWM | <1 μA - Negligible leakage current preserves efficiency in low-power standby circuits |
| Package | DO-214AC (SMA) - Industry-standard surface-mount outline with MSL 1 rating and J-STD-002 solderability |
Pinout & Package
DO-214AC (SMA) package: cathode-banded unidirectional device with two terminals-cathode (marked end) and anode-mounted in a molded plastic case meeting UL 94V-0 flammability rating and JESD201 Class 2 whisker resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Transient current sink | Connected to protected line; conducts surge current to ground when VREV > VBR |
| Anode | Reference/ground return | Typically tied to system ground or low-impedance return path for clamping loop integrity |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD stress per JEDEC standards |
| Glass-passivated junction | Enhances long-term stability of VBR and IR across humidity and thermal aging conditions |
| Fast response time <1.0 ps | Clamps ESD and fast transients before sensitive downstream circuitry is damaged |
| ISO 7637-2 compliance | Withstands defined automotive load-dump and inductive-switching pulses without degradation |
| MSL 1 rating | Zero floor-life limitation-safe for reflow without baking, simplifying SMT manufacturing flow |
Applications
| Automotive DC/DC Converter | Industrial SMPS Input Stage |
|---|---|
Use Scenario: Protects 24V input rail of buck converter against load dump and alternator transients in commercial vehicle ECUs. IC Role / Device Role / Timing Role: Unidirectional TVS placed between VIN and GND, acting as last-line clamp before primary controller IC. Use Value: Limits transient overshoot to ≤39.4V, preventing damage to 40V-rated MOSFETs and gate drivers while maintaining AEC-Q101 compliance. | Use Scenario: Shields AC-DC adapter output stage from back-fed surges during hot-plug or capacitor discharge events. IC Role / Device Role / Timing Role: Standoff-rated TVS on secondary-side 24V output, absorbing energy from reflected transients via transformer coupling. Use Value: 400W peak power rating sustains multiple 10/1000μs pulses without parametric shift, ensuring field-replaceable adapter longevity. |
| LED Driver Power Input | On-Board Charger (OBC) Auxiliary Supply |
Use Scenario: Safeguards constant-current LED driver ICs from inductive kickback when driving high-side MOSFET switches. IC Role / Device Role / Timing Role: Unidirectional clamp referenced to driver ground, activated only during negative-going transients on supply rail. Use Value: Low 22V VWM avoids false triggering during normal 24V nominal operation while clamping spikes to safe levels. | Use Scenario: Protects 12V auxiliary supply rail in EV on-board chargers from CAN bus coupling noise and relay bounce. IC Role / Device Role / Timing Role: TVS diode placed at OBC control board input, shunting coupled transients before LDO regulators and MCU power pins. Use Value: MSL 1 and matte tin plating ensure compatibility with lead-free reflow and long-term storage without oxidation risk. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ22A | Lower VBR range (24.4–26.9V); tighter tolerance; same VWM and VC (35.5V @ 11.3A) | Better suited for designs requiring lower clamping voltage and tighter VBR consistency | Select SMAJ22A if design prioritizes reduced clamping overshoot and tighter VBR distribution |
| SMBJ22C | Same VWM/VBR/VC specs but in larger DO-214AA (SMB) package; higher thermal mass and 600W PPPM rating | Preferred where PCB layout allows larger footprint and higher surge endurance is required | Choose SMBJ22C for enhanced thermal margin in high-temperature ambient or repetitive surge environments |
Compared with SMAJ22CH, SMAJ22A offers lower clamping voltage and tighter VBR spread for precision-sensitive rails, while SMBJ22C provides greater surge energy absorption and thermal resilience in space-tolerant layouts-neither is pin-compatible due to differing package outlines.
Availability
SMAJ22CH is available at Aetrix Electronics and suitable for automotive DC/DC converters, industrial SMPS inputs, and LED driver power stages requiring stable component supply with full AEC-Q101 traceability and MSL 1 handling.
Supply support for SMAJ22CH includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Taiwan Semiconductor Corporation (TSC) is a vertically integrated analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, specializing in TVS diodes, rectifiers, and power devices since 1979.
The SMAJ series was developed specifically for AEC-Q101-compliant automotive transient suppression, emphasizing robustness, tight parameter distributions, and seamless integration into automated SMT lines for Tier 1 suppliers.
FAQ
What is the clamping voltage of the SMAJ22CH under standard surge conditions?
The SMAJ22CH has a maximum clamping voltage (VC) of 39.4 V at 10.2 A peak pulse current, tested with the industry-standard 10/1000μs waveform. This value defines the upper voltage limit imposed on protected circuitry during transient events and is confirmed in the official Taiwan Semiconductor datasheet revision A2102. The SMAJ22CH maintains this clamping performance across its specified operating temperature range.
Is the SMAJ22CH suitable for automotive applications?
Yes, the SMAJ22CH is AEC-Q101 qualified and explicitly designed for automotive use. It meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b test requirements and is rated for junction temperatures from –55°C to +150°C. Its DO-214AC package carries MSL 1 rating and matte tin plating compliant with J-STD-002, making the SMAJ22CH appropriate for under-hood and ECU-level deployment.
What does the "CH" suffix indicate in SMAJ22CH?
The "CH" suffix in SMAJ22CH denotes a unidirectional configuration with a cathode band marking and standard polarity orientation. It distinguishes the part from bidirectional variants (e.g., SMAJ22C) and confirms compliance with the electrical specifications listed for the CH-series in the Taiwan Semiconductor datasheet. The SMAJ22CH is not interchangeable with CAH or C variants without verifying circuit polarity and surge directionality.
How does the SMAJ22CH compare to SMAJ22AH in terms of breakdown voltage?
The SMAJ22CH has a VBR range of 24.4–29.8 V, whereas SMAJ22AH specifies 24.4–26.9 V-indicating tighter VBR distribution for the AH variant. Both share identical VWM (22 V) and package (DO-214AC), but SMAJ22CH's broader VBR span reflects standard-grade tolerance versus the tighter binning of SMAJ22AH. Designers selecting the SMAJ22CH should account for this wider variation in turn-on threshold.
What is the maximum steady-state power dissipation for the SMAJ22CH?
The SMAJ22CH has a maximum steady-state power dissipation (PD) of 1 W at TA = 25°C, as specified in the Absolute Maximum Ratings table. This rating applies to continuous DC or low-frequency reverse bias conditions-not transient events. Derating is required above 25°C ambient, per the pulse derating curve in Figure 2 of the Taiwan Semiconductor datasheet. For surge protection, the relevant metric remains the 400W peak pulse power (PPPM) rating.
SMAJ22CH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AC, SMA
- Series:
- SMAJ
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 22V
- Voltage - Breakdown (Min):
- 24.4V
- Voltage - Clamping (Max) @ Ipp:
- 39.4V
- Current - Peak Pulse (10/1000µs):
- 10.2A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ22CH FAQ
1.How can I place an order for SMAJ22CH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ22CH on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SMAJ22CH reliable?
The price and inventory of SMAJ22CH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ22CH is usually 5 days.
3.What payment methods are accepted for SMAJ22CH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ22CH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ22CH?
SMAJ22CH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ22CH order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SMAJ22CH?
For technical support, including SMAJ22CH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ22CH requirements.
6.How does Aetrix verify that SMAJ22CH is sourced from the original manufacturer or authorized distributors?
All SMAJ22CH products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SMAJ22CH meets industry standards.
7.What is the process for return or replacement of SMAJ22CH?
All SMAJ22CH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ22CH, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SMAJ22CH part is unused and in its original packaging.
Return procedure for SMAJ22CH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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